Waters BioSuite ion-exchange column offerings include strong and weak, cation (CXC) and anion-exchangers (AXC) bonded to a pH stable (i.e., pH 2 -12), methacrylic ester-based polymeric resin. The availability of four separation chemistries provides chromatographers with the flexibility required to develop methods that separate proteins and / or peptides based upon minor charge differences. Nonporous (NP) and porous IEX columns are also available. Superior chromatographic resolution is possible using the nonporous IEX offerings however, greater binding capacity is obtained with the porous selections. In addition, selected BioSuite ion-exchange columns are available in PEEK hardware as well as in 21.5 mm preparative column sizes.